A giant ash cloud from an erupting volcano in Papua New Guinea is disrupting flights.
Qantas has re-routed its Sydney to Tokyo, Narita, and Sydney to Shanghai flights to dodge the cloud.
Flights QF21, QF22 and QF130 will fly over central PNG to avoid the cloud over Rabaul.
“The new flight paths won't really impact the flight time,” a Qantas spokesperson told AAP.
“It will be five minutes if anything.”
The Mount Tavurvur volcano has erupted in eastern PNG, spewing rocks and ash into the air and forcing the evacuation of local communities.
The volcano, which destroyed the town of Rabaul when it erupted simultaneously with nearby Mount Vulcan in 1994, rumbled to life early this morning on the tip of the island of New Britain.
The volcano is spewing rocks and ash into the air, forcing the evacuation of local communities.
The Australian government issued a warning against travelling to the area.
"Authorities have evacuated communities close to the volcano. Residents of Rabaul town have been advised to remain indoors to avoid falling ash," it said.
There were no immediate reports of injuries or damage.
The Volcanic Ash Advisory Centre in Darwin said the ash cloud was drifting southeast.
"The eruption was to 60,000 feet, which is flight level. There was two hours of high-level eruption," an official from the centre, Cyndee Feals, told AFP.
"The ash was initially blowing to the southwest but has now turned to the southeast and we expect it to clip the edge of Australian airspace later today, but we don't expect ash over Australia."
She said planes may be forced to take alternative routes, with the ash forecast to move towards the Solomon Islands and then Vanuatu in the Pacific.
Australian flag carrier Qantas said three flights had been re-routed to avoid the ash cloud in the east of PNG.
In Rabaul, the ground was covered in a layer of ash, local reports said.
"Police have cautioned people not to panic but remain indoors and listen to local Radio East New Britain for updates," the PNG loop website said.
"The situation has eased except for the rumbling and roaring as rocks are shot into the air."
Its correspondent in Rabaul added that "all shops are closed. The provincial disaster officials are in town".
The 688-metre volcano has erupted several times before, notably 20 years ago.
In 1994, major eruptions at both Tavurvur and nearby Mount Vulcan destroyed much of Rabaul, with falling ash causing buildings to collapse, and while loss of life was minimal due to a quick evacuation, looters ransacked the town.